Medical Marijuana: Review Shows Pot Helps These Conditions

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Medical marijuana may provide some benefit for patients with
chronic nerve pain or cancer pain, as well as people who have
multiple sclerosis and experience muscle spasms, according to a
new review study.

However, there is not much evidence supporting the use of medical
marijuana for other reasons, such as sleep disorders, Tourette
syndrome and anxiety disorders. And marijuana doesn't appear to
help people with
depression or psychosis, or those with eye pressure from
glaucoma, the study found.

Still, many of the studies done to date that found that marijuana
had little or no effect were small, or lacked a rigorous design,
the researchers said. Larger, more robust studies are needed to
confirm the medical effects of cannabinoids, the compounds that
are the active ingredients in marijuana, the researchers
said in their findings, published today (June 23) in the Journal
of the American Medical Association.

"There is evidence to support the use of cannabinoids for the
treatment of chronic pain and spasticity," said study co-author
Penny Whiting, a senior research fellow in epidemiology and
health services research at the University of Bristol in the
United Kingdom "However, this needs to be balanced against
an increased risk of side effects," which can include dizziness,
dry mouth, nausea and sleepiness, Whiting said.

"Individuals considering cannabinoids as a possible treatment for
their symptoms should discuss the potential benefits and harms
with their doctor," Whiting said.

The new findings raise important issues, given that 23 states
have laws allowing the use of medical
marijuana for various conditions, said Dr. Deepak Cyril
D'Souza and Dr. Mohini Ranganathan, of the Yale University School
of Medicine, who wrote an editorial accompanying the new study.

"For most qualifying conditions [for medical marijuana], approval
has relied on low-quality scientific evidence, anecdotal reports,
individual testimonials, legislative initiatives and public
opinion," D'Souza and Ranganathan wrote. "Imagine if other drugs
were approved through a similar approach."

If the goal of legalizing medical marjiuana is to make it
available for medical purposes, then "it is unclear why the
approval process should be different from that used for other
medications," D'Souza and Ranganathan said. "Since medical
marijuana is not a life-saving intervention, it may be prudent to
wait before widely adopting its use until high-quality evidence
is available." [ Where
Americans Smoke and Grow Marijuana (Maps) ]

The new review, analyzed information from nearly 80 studies that
included about 6,500 people total, in which participants were
randomly assigned to take cannabinoids, a placebo or another
drug. The cannabinoids tested in the study included compounds
from the cannabis
plant, such as THC (tetrahydrocannabinol) and CBD
(cannabidiol), or synthetic compounds such as dronabinol and
nabilone.

According to an analysis of eight studies that looked at
cannabinoids for patients with nerve and cancer pain, patients
using the substances were about 40 percent more likely than the
people using a placebo to report a reduction in their pain of at
least 30 percent.

Some studies suggested that people with MS who took cannabinoids
experienced improvements in their
muscle spasms.

There was also some evidence that cannabinoids helped with nausea
and vomiting in patients undergoing chemotherapy: In an analysis
of three studies, 47 percent of patients using cannabinoids had
their nausea and vomiting completely stop, while only about 20
percent in the placebo group had these symptoms completely stop.
Some drugs, including dronabinol and nabiximol, are approved to
treat chemotherapy-induced nausea and vomiting.

There was no evidence of benefit for people with depression,
psychosis or glaucoma, but the studies of marijuana use by people
with these conditions were small, and in the case of depression,
the studies were conducted primarily to look at other outcomes,
such as chronic pain.

Common side effects from marijuana included dizziness, dry mouth,
nausea, fatigue, drowsiness, vomiting, disorientation, confusion,
loss of balance and hallucination.

Although the acute effects of marijuana are well known, more
studies are needed on the effects of repeated exposure to
marijuana, which would occur among patients who use the drug
regularly for medical purposes, the editorial said.

About 1 in 10 marijuana users develops addiction to the drug, and
users can also develop a tolerance, meaning that the dosing of
the drug may have to be increased over time to have the same
effect, the editorial said.